Pathologists and hematologists base the diagnosis and classification of lymphoma and leukemia on morphologic criteria. Patients are treated accordingly. In a previous study we demonstrated a general correlation between the morphologic type of lymphoid neoplasm and the volume and synthetic DNA content of its cells as measured by electronic means. In the proposed study we will determine the value of flow microfluoremetry (FMF) as a quantitative approach to the diagnosis and classification of these malignancies. FMF allows analysis of physical characteristics and biochemical contents of large numbers of cells in a relatively short time. Using freshly prepared cell suspensions from surgical specimens, peripheral blood, bone marrow or serosal effusions, cell size, cell protein, surface-bound immunoglobulin (SIg) and DNA distributions will be analyzed singly or in combination. Cellular DNA content analysis will permit a rapid determination of percentages of cells in the various phases of the cell cycle as well as an assessment of abnormal contents of cellular DNA (aneuploidy). DNA synthesis will be studied in parallel by thymidine incorporation and autoradiography. Whenever applicable, selective DNA analysis of subpopulations of malignant cells will be performed in samples containing heterogeneous cell populations, using cell size and "monoclonal" SIg as general markers for malignancy. This evaluation will be performed either by simultaneous dual parameter analysis in unseparated cell populations or by the use of the sorting capabilities of the FMF. Needle aspirates will be performed in solid tissues prior to the preparation of the cell suspensions, in order to evaluate such a technique as a possible means for monitoring response to therapy. The results of the analysis will be compared with the conventional morphologic diagnosis of the samples. Correlations will be made with the clinical behavior of the neoplasms.